API and business language schema design framework for message exchanges

ABSTRACT

A server system facilitates an exchange of messages with a remote client application. The server system includes a plurality of application servers hosting a plurality of applications. A plurality of Application Program Interfaces (APIs) provides programmatic access to the plurality of applications, each of the APIs being configured to receive request messages compiled by the remote client application. First and second request messages, respectively addressed to first and second APIs of the plurality of APIs by a remote client application, each comprise at least one common data component. Further, the first request message includes a first payload specific to the first API, and the second request message includes a payload specific to the second API.

RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.12/771,981, filed Apr. 30, 2010, entitled “API and Business LanguageSchema Design Framework for Message Exchanges,” which is a continuationof U.S. application Ser. No. 10/997,767, filed Nov. 24, 2004, entitled“API and Business Language Schema Design Framework/or MessageExchanges,” which claims the priority benefit of the filing date of U.S.Provisional Application No. 60/524,782, filed Nov. 24, 2003, entitled“Business Language Schema Design Framework for Message Exchanged inTrading Community,” which are incorporated herein, in their entirety, byreference.

COMPUTER LISTING

A computer listing is attached as an Appendix.

FIELD OF THE INVENTION

The present application relates generally to the technical field ofapplication program interfaces (APIs) and language schemas.

BACKGROUND

Buyers, sellers, and other business partners, are increasingly utilizingelectronic trading systems (e.g., electronic marketplaces) tocollaborate and to do business with each other. Part of thiscollaboration may involve, for example, linking operational businessprocesses. Business processes may be linked by the exchange ofinformation, in agreed sequences and within agreed timeframes, betweenbuyer and seller applications, and affiliated third party businessservice providers.

To facilitate the above-mentioned exchange of business information,buyer and seller applications, as well as applications of third partybusiness service providers, may expose Application Program Interfaces(APIs) which allow applications to make calls (e.g., function calls) toother applications to either request or send information. However, asthe number of buyers, sellers, and third party applicationsparticipating in the exchange of business information increases, thetechnical challenge of enabling this multitude of applications toexchange information increases. For example, the development ofapplications that are able to access APIs of a large number of otherapplications becomes increasingly burdensome and technicallychallenging.

SUMMARY OF THE INVENTION

According one aspect of the present invention, there is provided aserver system to facilitate an exchange of messages with a remote clientapplication. The server system includes a plurality of applicationservers hosting a plurality of applications. A plurality of ApplicationProgram Interfaces (APIs) provides programmatic access to the pluralityof applications, each of the APIs being configured to receive requestmessages compiled by the remote client application. First and secondrequest messages, respectively addressed to first and second APIs of theplurality of APIs, each comprise at least one common data component.Further, the first request message includes a first payload specific tothe first API, and the second request message includes a payloadspecific to the second API.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a network diagram depicting a trading system, within which anexemplary embodiment of the present invention may be deployed, having aclient-server architecture.

FIG. 2 is a block diagram illustrating multiple marketplace and paymentapplications that, in one exemplary embodiment of the present invention,form part of a commerce server system.

FIG. 3 is a high-level entity-relationship diagram illustrating varioustables that may be maintained within databases utilized by themarketplace and payment applications described with reference to FIG. 2.

FIG. 4 is a block diagram illustrating further details regarding anexemplary trading system, configured according to one of embodiment ofthe present invention.

FIG. 5 is a block diagram illustrating the architecture of an exemplarythird party application, configured according to one embodiment of thepresent invention, to communicate with a commerce server system thatexposes a number of APIs.

FIG. 6 is a block diagram illustrating the architecture of an APIserver, according to an exemplary embodiment of the present invention.

FIG. 7 is a block diagram illustrating structural details of exemplaryabstract request and response messages.

FIG. 8 is a block diagram illustrating that the structure of an abstractrequest-response message may be extended to a specific item listing andpayment requests, in one exemplary embodiment of the present invention.

FIG. 9 is a flowchart illustrating a method, according to an exemplaryembodiment of the present invention, to communicate messages between aclient application and an API server of a plurality of API servers.

FIG. 10 is a flowchart illustrating a method, according to an embodimentof the present invention, of performing version management between aclient application and an API.

FIG. 11 is a block diagram representation of a machine, in the exemplaryform of a computer system, within which a set of instructions forcausing the machine to perform any one or more of the methodologiesdiscussed herein may be executed.

DETAILED DESCRIPTION

A business language schema design framework for message exchanges in atrading system is described. In the following description, for purposesof explanation, numerous specific details are set forth in order toprovide a thorough understanding of the present invention. It will beevident, however, to one skilled in the art that the present inventionmay be practiced without these specific details.

An exemplary embodiment of the present invention is discussed belowwithin the context of a network-based commerce system that supports anetwork-based, electronic marketplace. Buyers and sellers, utilizingbuyer and seller applications, as well as third party business serviceproviders, interact utilizing the electronic marketplace as a forum.Business processes may be driven by a wider range of electronicmarketplace operational considerations, so as to enable buyers andsellers to conduct transactions utilizing the electronic marketplace. Inone embodiment of the present invention, a buyer and sellercommunication model is proposed that identifies the requirements formessage exchange sequences, message exchange timings, and the purpose ofeach message exchange.

In one embodiment, message exchanges comply with a business languageschema component model. The business language schema design frameworkenables an electronic marketplace server system (e.g., the commercesystem) to support a wide range of commerce transactions, includingauction, fixed price buying and selling, product catalogs searches andpayments. These transactions provide examples of communications betweenbuying and selling applications via the electronic marketplace, as wellas communications with other third party business service providers.

In an exemplary embodiment, there is provided a schema component modelthat provides an abstract definition of the business message payloads.Payloads may be defined in a way to support extensibility which enablesother types of commerce transactions models to be made available via themarketplace (e.g., for electronic procurement, reverse auctioning,credit check, and shipment/logistic activities).

The business language schema catalogs common business message componentsthat may be utilized for any number of business communicationsfacilitated by an electronic marketplace (e.g., auction, fixed pricebuying and selling, product catalog search, catalog-based listings, andelectronic payment in support of item purchases). The business languageschema, in one embodiment, enables a wide range of business applicationsto interoperate with XML web services APIs, and externally located andinternally hosted clients.

Request/response message payload components are defined by the businesslanguage schema which may be utilized to enable the building of a rangeof messages that may flow back and forth from buyers, sellers and thirdparty business service providers to marketplace XML web services, theseweb services enabling trading parties to list, find, and sell items andservices.

In various exemplary embodiments, message exchanges may be made,utilizing the business-language based message exchange model of anexemplary embodiment of the present invention, with both external andinternal business applications over synchronous communication andasynchronous communication links. Further, document-oriented synchronousmessaging, as well as document-oriented asynchronous messaging, may besupported. As will be described in further detail below, a messagepackaging format may be a flavor of the XML messaging format (e.g., SOAP1.1, SOAP 1.2, ebXML, or an e-mail format such as MIME or any otherarbitrary message packaging format). Further, transport protocols usedmay include HTTP, HTTPS, SMTP, or some other arbitrary transportprotocol needed for particular business applications hosted remotely ata trading entity that requires moving data.

A schema design framework for a business language is accordinglyprovided, in an exemplary embodiment of the present invention, tosupport message payload definitions for a multitude of use cases and foruse with a multitude of APIs. This may be accomplished via anextensibility model that includes base components, and business messagecomponents that support new transaction models and messaging components.Specifically, the base components provide a definition of basic corecomponent types, basic components and aggregate components, including anabstract messaging framework. The business message components are basedon the business information requirements for a particular use case.

Regarding the business messaging components, based on the businessinformation requirements of a particular use case, the definitions ofthe basic set of messaging components are needed for a legacytransaction model can be supported utilizing the above mentioned basecomponents in support of business message components. In one exemplaryembodiment, the business language components for use in an electronictrading environment, such as that described below with respect to FIG.1, may include: item, item transaction, shipping details, payment,address, user, buyer, seller and transaction components.

It will be appreciated that, over the course of time, many new types ofbusiness processes may be employed by a trading community (e.g., buyers,sellers and third party service providers) that utilize an electronicmarketplace and accordingly that interface with services exposed by theelectronic marketplace. Such new types of applications may exploitdifferent types of transaction interfaces (e.g., APIs) exposed by anelectronic marketplace. An exemplary embodiment of the present inventionenables the reusability of certain components, both at a messaging andan application level, while providing for the extensibility toaccommodate such new types of business processes and applications.Accordingly, an exemplary embodiment of the present invention proposesan abstract message payload framework that can be extended for manydifferent types of messages and over different protocols, as may berequired.

Accordingly, in one embodiment, the business language schema designframework of the present invention may be utilized to achievereusability, layering, extensibility, as well as ease of use andinteroperability between a number of business processes andapplications.

Further, the exemplary business language schema design framework seeksto avoid XML Schema Definition (XSD) features that presentinteroperability issues (e.g., WSDL and SOAP) in processes deployed onclient application runtimes. Further, the exemplary framework seeks totake advantage of a wide a range of client run-time environments anddevelopment tools (e.g., ranging from public domain to commerciallyavailable software), and to decrease the cost of maintenance to clientsto easily interpret messages by exploiting underlying reusable base andaggregate business components as well as extensibility features. Anembodiment of the present invention also seeks to import, extend and orrestrict schemas for a wide range of “enumerated” code types (e.g., ISO,currency and country codes) to use name spaces that enable modularity ofbusiness message components and corresponding XML web services APIs thatconsume and produce the resulting messages, and to satisfy thecustomization and extensibility needs of widely differing tradingcommunities and transaction models. For example, the business languageschema design framework seeks to be reusable in consumer-to-consumer(C2C), business-to-consumer (B2C), and business-to-business (B2B)trading communities.

In order to facilitate a framework for standardizing businessinformation semantics in a flexible and yet interoperable manner,according to one embodiment, there may be provided application-specificmessage payload components that link back to a common set of core datacomponents from which they are derived. Below are described corecomponent concepts.

Business Language Schema Component Concepts

Core Component Type (CCT): a core component type is, in one embodiment,a low level construct that may have no meaning on its own. A corecomponent type has a content component and additional components (e.g.,mandatory or optional) which give it a specific meaning. An example of acore component type is an “amount”, where the content part is a number(e.g., 87) and another required part is a unit (e.g., a Euro).

Basic core components: a basic core component represents, in theexemplary embodiment, a core business concept (e.g., a unique businesssemantic definition). This may be accomplished by employing a corecomponent type (CCT) or a primitive data type (e.g., XSD data types) towhich some other semantically unique object (e.g., a “weight” element isan instance of the core component type CCT Measure Type).

Aggregate core components: aggregate core components, in one exemplaryembodiment, encapsulate two or more basic core components whichrepresent higher-level business concepts (e.g., “shipping address” is aninstance of Address Type). Each aggregate core component may have itsown business semantic definition.

Having above provided a high level introduction, amore detaileddescription of an exemplary trading system, centered around anetwork-based commerce system, will now be described with reference toFIGS. 1-3.

Platform Architecture

FIG. 1 is a network diagram depicting a trading environment 10,according to one exemplary embodiment of the present invention, having aclient-server architecture. A commerce server system, in the exemplaryform of a network-based commerce system 12, provides server-sidefunctionality, via a network 14 (e.g., the Internet) to one or moreclients. FIG. 1 illustrates, for example, a web client 16 (e.g., abrowser, such as the Internet Explorer browser developed by MicrosoftCorporation of Redmond, Wash. State), and a programmatic client 18executing on respective client machines 20 and 22.

Turning specifically to the network-based commerce system 12, anApplication Program Interface (API) server 24 and a web server 26 arecoupled to, and provide programmatic and web interfaces respectively to,one or more application servers 28. Specifically, the API server 24exposes multiple APIs to users of the commerce system 12. Each of theseAPIs supports one or more function calls to applications of the system12.

The application servers 28 host one or more marketplace applications 30and payment applications 32. The application servers 28 are, in turn,shown to be coupled to one or more databases servers 34 that facilitateaccess to one or more databases 36.

The marketplace applications 30 provide a number of marketplacefunctions and services to users that access the commerce system 12. Thepayment applications 32 likewise provide a number of payment servicesand functions to users. The payment applications 30 may allow users toquantify for, and accumulate, value (e.g., in a commercial currency,such as the U.S. dollar, or a proprietary currency, such as “points”) inaccounts, and then later to redeem the accumulated value for products(e.g., goods or services) that are made available via the marketplaceapplications 30. While the marketplace and payment applications 30 and32 are shown in FIG. 1 to both form part of the network-based commercesystem 12, it will be appreciated that, in alternative embodiments ofthe present invention, the payment applications 32 may form part of apayment service that is separate and distinct from the commerce system12.

Further, while the system 10 shown in FIG. 1 employs a client-serverarchitecture, the present invention is of course not limited to such anarchitecture, and could equally well find application in a distributed,or peer-to-peer, system. The various marketplace and paymentapplications 30 and 32 could also be implemented as standalone softwareprograms, which do not necessarily have networking capabilities.

The web client 16, it will be appreciated, accesses the variousmarketplace and payment applications 30 and 32 via the web interfacesupported by the web server 26. Similarly, the programmatic client 18accesses the various services and functions provided by the marketplaceand payment applications 30 and 32 via the programmatic interfaceprovided by the API server 24. The programmatic client 18 may, forexample, be a seller application (e.g., the TurboLister applicationdeveloped by eBay Inc., of San Jose, Calif.) to enable sellers to authorand manage listings on the commerce system 12 in an off-line manner, andto perform batch-mode communications between the programmatic client 18and the network-based commerce system 12.

FIG. 1 also illustrates a third party application 38, executing on athird party server machine 40, as having programmatic access to thenetwork-based commerce system 12 via the programmatic interfacesprovided by the API server 24. For example, the third party application38 may, utilizing information retrieved from the network-based commercesystem 12, support one or more features or functions on a website hostedby the third party. The third party website may, for example, provideone or more promotional, marketplace or payment functions that aresupported by the relevant applications of the network-based commercesystem 12.

Marketplace Applications

FIG. 2 is a block diagram illustrating multiple marketplace and paymentapplications 30 that, in one exemplary embodiment of the presentinvention, are provided as part of the network-based commerce system 12.The commerce system 12 may provide a number of listing and price-settingmechanisms whereby a seller may list goods or services for sale, a buyercan express interest in or indicate a desire to purchase such goods orservices, and a price can be set for a transaction pertaining to thegoods or services. To this end, the marketplace applications 30 areshown to include one or more auction applications 44 which supportauction-format listing and price setting mechanisms (e.g., English,Dutch, Vickrey, Chinese, Double, Reverse auctions etc.). The variousauction applications 44 may also provide a number of features in supportof such auction-format listings, such as a reserve price feature wherebya seller may specify a reserve price in connection with a listing and aproxy-bidding feature whereby a bidder may invoke automated proxybidding.

A number of fixed-price applications 46 support fixed-price listingformats e.g., the traditional classified advertisement-type listing or acatalogue listing) and buyout-type listings. Specifically, buyout-typelistings (e.g., including the Buy-It-Now (BIN) technology developed byeBay Inc., of San Jose, Calif.) may be offered in conjunction with anauction-format listing, and allow a buyer to purchase goods or services,which are also being offered for sale via an auction, for a fixed-pricethat is typically higher than the starting price of the auction.

Store applications 48 allow sellers to group their listings within a“virtual” store, which may be branded and otherwise personalized by andfor the sellers. Such a virtual store may also offer promotions,incentives and features that are specific and personalized to a relevantseller.

Reputation applications 50 allow parties that transact utilizing thenetwork-based commerce system 12 to establish, build and maintainreputations, which may be made available and published to potentialtrading partners. Consider that where, for example, the network-basedcommerce system 12 supports person-to-person trading, users may have nohistory or other reference information whereby the trustworthiness andcredibility of potential trading partners may be assessed. Thereputation applications 50 allow a user, for example through feedbackprovided by other transaction partners, to establish a reputation withinthe network-based commerce system 12 over time. Other potential tradingpartners may then reference such a reputation for the purposes ofassessing credibility and trustworthiness.

Personalization applications 52 allow users of the commerce system 12 topersonalize various aspects of their interactions with the commercesystem 12. For example a user may, utilizing an appropriatepersonalization application 52, create a personalized reference page atwhich information regarding transactions to which the user is (or hasbeen) a party may be viewed. Further, a personalization application 52may enable a user to personalize listings and other aspects of theirinteractions with the commerce system 12 and other parties.

In one embodiment, the network-based commerce system 12 may support anumber of marketplaces that are customized, for example, for specificgeographic regions. A version of the commerce system 12 may becustomized for the United Kingdom, whereas another version of thecommerce system 12 may be customized for the United States. Each ofthese versions may operate as an independent marketplace, or may becustomized (or internationalized) presentations of a common underlyingmarketplace.

Navigation of the network based-commerce system 12 may be facilitated byone or more navigation applications 56. For example, a searchapplication enables key word searches of listings published via thecommerce system 12. A browse application allows users to browse variouscategory, catalogue, or inventory data structures according to whichlistings may be classified within the commerce system 12. Various othernavigation applications may be provided to supplement the search andbrowsing applications.

In order to make listings, available via the network-based commercesystem 12, as visually informing and attractive as possible, themarketplace applications 30 may include one or more imaging applications58 utilizing which users may upload images for inclusion withinlistings. An imaging application 58 also operates to incorporate imageswithin viewed listings. The imaging applications 58 may also support oneor more promotional features, such as image galleries that are presentedto potential buyers. For example, sellers may pay an additional fee tohave an image included within a gallery of images for promoted items.

Listing creation applications 60 allow setters conveniently to authorlistings pertaining to goods or services that they wish to transact viathe commerce system 12, and listing management applications 62 allowsetters to manage such listings. Specifically, where a particular sellerhas authored and/or published a large number of listings, the managementof such listings may present a challenge. The listing managementapplications 62 provide a number of features (e.g., auto-relisting,inventory level monitors, etc.) to assist the seller in managing suchlistings. One or more post-listing management applications 64 alsoassist sellers with a number of activities that typically occurpost-listing. For example, upon completion of an auction facilitated byone or more auction applications 44, a seller may wish to leave feedbackregarding a particular buyer. To this end, a post-listing managementapplication 64 may provide an interface to one or more reputationapplications 50, so as to allow the seller conveniently to providefeedback regarding multiple buyers to the reputation applications 50.

Dispute resolution applications 66 provide mechanisms whereby disputesarising between transacting parties may be resolved. For example, thedispute resolution applications 66 may provide guided procedures wherebythe parties are guided through a number of steps in an attempt to settlea dispute. In the event that the dispute cannot be settled via theguided procedures, the dispute may be escalated to a third partymediator or arbitrator.

A number of fraud prevention applications 68 implement various frauddetection and prevention mechanisms to reduce the occurrence of fraudwithin the commerce system 12.

Messaging applications 70 are responsible for the generation anddelivery of messages to users of the network-based commerce system 12,such messages for example advising users regarding the status oflistings at the commerce system 12 (e.g., providing “outbid” notices tobidders during an auction process or to provide promotional andmerchandising information to users).

Merchandising applications 72 support various merchandising functionsthat are made available to sellers to enable sellers to increase salesvia the commerce system 12. The merchandising applications 80 alsooperate the various merchandising features that may be invoked bysellers, and may monitor and track the success of merchandisingstrategies employed by sellers.

The network-based commerce system 12 itself, or one or more parties thattransact via the commerce system 12, may operate loyalty programs thatare supported by one or more loyalty/promotions applications 74. Forexample, a buyer may earn loyalty or promotions points for eachtransaction established and/or concluded with a particular seller, andbe offered a reward for which accumulated loyalty points can beredeemed,

Data Structures

FIG. 3 is a high-level entity-relationship diagram, illustrating varioustables 90 that may be maintained within the databases 36, and that areutilized by and support the marketplace and payment applications 30 and32. A user table 92 contains a record for each registered user of thenetwork-based commerce system 12, and may include identifier, addressand financial instrument information pertaining to each such registereduser. A user may, it will be appreciated, operate as a seller, a buyer,or both, within the network-based commerce system 12. In one exemplaryembodiment of the present invention, a buyer may be a user that hasaccumulated value (e.g., commercial or proprietary currency), and isthen able to exchange the accumulated value for items that are offeredfor sale by the network-based commerce system 12.

The tables 90 also include an items table 94 in which are maintaineditem records for goods and services that are available to be, or havebeen, transacted via the commerce system 12. Each item record within theitems table 94 may furthermore be linked to one or more user recordswithin the user table 92, so as to associate a seller and one or moreactual or potential buyers with each item record.

A transaction table 96 contains a record for each transaction (e.g., apurchase transaction) pertaining to items for which records exist withinthe items table 94.

An order table 98 is populated with order records, each order recordbeing associated with an order. Each order, in turn, may be with respectto one or more transactions for which records exist within thetransactions table 96.

Bid records within a bids table 100 each relate to a bid received at thenetwork-based commerce system 12 in connection with an auction-formatlisting supported by an auction application 44. A feedback table 102 isutilized by one or more reputation applications 50, in one exemplaryembodiment, to construct and maintain reputation information concerningusers. A history table 104 maintains a history of transactions to whicha user has been a party. One or more attributes tables 106 recordattribute information pertaining to items for which records exist withinthe items table 94. Considering only a single example of such anattribute, the attributes tables 106 may indicate a currency attributeassociated with a particular item, the currency attribute identifyingthe currency of a price for the relevant item as specified in by aseller.

Having above described an exemplary trading environment 10, within whichan exemplary embodiment of the present invention maybe deployed, furtherdetails regarding a business language schema design framework, accordingto an exemplary embodiment of the present invention, for messageexchanges (e.g., within the trading environment 10) are now described.FIG. 4 is block diagram illustrating a client-server architecture thatmay be deployed, for example, as part of the trading environment 10described above with reference to FIG. 1. Referring specifically to FIG.4, abstract request/response messages 120 are sent between one of Nthird party systems, such as third party system 122, and a server system125 that is accessed via a number of APIs exposed by respective APIservers 24

Thus, in broad terms, the third party system 122, using the clientapplication 124, compiles a request message, which is directed to an API126 (e.g., AddItem, GetItemTransaction, etc.) of the server system 125.Each API 126 in turn provides access through supported function calls toone of a plurality of applications, indicated generally by arrow 128,that have access to a database 130.

Turning now to FIG. 5, further details regarding the exemplary clientapplication 124, hosted on a third party system 122, are shown. Theclient application 124 includes an abstract request/response messageprocess component 136 for processing the request/response messages 120shown in FIG. 4. In particular, the abstract request/response messageprocess component 136 comprises an Error Processor 138 and a VersionProcessor 140. The client application 134 further comprises anAPI-specific component 142 that includes XML schema definitions 144, 146for the various API's 126 with which the client application 124 isconfigured to communicate (e.g., API_0 and API_1 shown in FIG. 4). Anumber of possible front end transport technologies, such as SOAP, MIMEand HTTP, are shown to be supported by a transport handler 13.

The client application 124 also includes a message handler 145, and aserialization/deserialization handler 147, in addition to the APIspecific component 142. Specifically, each third party system 122 mayhost a client application 124, which can exploit the abstractrequest/response message via any one of the following processingcomponents:

i) A transport handler 143 which supports the communication protocole.g., HTTP, HTTPS, SMTP, etc;

ii) A message handler 145 which supports the message envelope processingcapabilities, e.g., HTTP, POST Raw Data stream, SOAP, MIME, etc.;

iii) Abstract request serialization and response deserialization handler147; and

iv) Client-side API specific application components 142.

The transport handler 143 and the message handler can be formed from anystandard, commercially available Software Development Kit (SDK) to whicha third party has access in its development and runtime deploymentenvironments.

The abstract request serialization and response deserialization handler147 can be developed for client applications 124 once, and reusedmultiple times, thus reducing the cost of interfacing and also providingconsistent interfacing with API-based application services exposed bythe commerce system 12 over a wide range of transport and messagingparticles. Such a “write once and, use multiple times” deployment isuseful for trading communities, regardless of use case and otherinfrastructure components in support of transport, security andmessaging protocols.

Turning now to FIG. 6, at the server side, an exemplary API Server 148comprises a front end Presentation tier 150, which receives requestmessages and sends response messages, a Business tier 152 and a Datacomponents tier 154. The Business tier 152 includes componentscorresponding to the various APIs, indicated generally by arrow 156. Thebenefits on the server side in terms of creating response payloads isthat, as for request payloads, basic response components are compilableusing reusable components

The structure of exemplary abstract request and response messages 158,176 wilt now be described in detail with reference to FIG. 7. Referringfirst to the abstract request message 158, an exemplary abstract requestmessage 158 comprises a Detail Level component 160 and an associatedDetailCodeType 162. This advantageously allows the client application124 to request a required level of detail within a listing, for example,relating to a particular item listed on the commerce system 12. Thelevel of detail requested may range from a most detailed to a leastdetailed level. The abstract request message 158 further comprises anError Language component 164 and an associated Language IdentificationTag 166, and a Version_ID component 168 and an associated VersionIdentifier 170. The abstract request message 158 is then completed byproviding a Request Payload component 172, for carrying any type of XMLdata 174.

An exemplary abstract response message 176 includes a Time Stampcomponent 178 and an associated DateTime 180, and an Acknowledgementcomponent 182 and an associated AckCodeType 184. These components areused to acknowledge receipt of a request message of the received from aclient application 124.

The abstract response message 176 further includes a Correlation_IDcomponent 186 and associated String Identifier 188, an Error(s) Datacomponent 190 and associated data 192, a Version_ID 193, a Buildcomponent 194 and a Response Payload component 196 for receiving anytype of XML data 198.

The Correlation_ID component 186 and associated String identifier 188allow the abstract response message 176 to be correlated with aparticular incoming request message 158, and to indicate thiscorrelation to the requesting client application 124.

Thus, there is some commonality in the abstract request and abstractresponse messages 158 and 176, namely they both can carry any type ofdata, and both include version information.

The Error Language component 164 and the Error Data(s) component 190ensure that the API request/response messages consistently use, manageand communicate error components. Part of this is the ability tocommunicate versioning information identifying what version of an API aparticular API server 24 is using to communicate with a clientapplication 124 of a third party system 122 (e.g., a client 20 and 22).Thus, for example, if a third party system 122 sends a request messagethat includes incorrect data or that does not comply with the publishedrequirements of a target API, the Error Data(s) component 190 is used bythe target API to communicate information regarding the error back tothe client application 124. Thus, when an error is detected, a responsemessage is generated by the relevant API, this response message beingeither a long message or a short message, and including an error codeand associated severity code. This response message is sent to therelevant client application 124, thereby informing the clientapplication 124 as to the nature of the error.

Regarding the version of the API that the API server 24 is using,versioning information is included in both a request message from aclient application 124 to the API server 24, as well as a responsemessage from the API server 24 back to the client application 124. Thisis indicated schematically by blocks 168 and 193 in FIG. 7. Thus, therespective version components in the request and response messagesindicate a particular version of the API on the API server 24. In sodoing, and in view of the fact that the API version used by the APIserver 24 typically changes, the client application 124 will have a wayof detecting when it needs to upgrade the schema that it uses to formatand generate request messages to the relevant.

An embodiment of the present invention facilitates extension of thebehavior of the APIs in terms of the request and response messagestructures. In other words, the abstract request and response models canbe extended to enable API requests and responses between a third partysystem 122 and any number of APIs provided by one or more API servers24. For example, a particular server system may expose a number of APIs,each conforming to the basic request/response messages described above.Thus, for example, the basic request/response messages can be extendedto enable an AddItem API, or a GetItem API, or a GetAccount API. Thus,for example, for a third party system wishing to exchange iteminformation with the commerce system 12, the basic abstract requestmessage may be extended with the addition of information conforming to aschema understood by a GetItem API.

In other words, this arrangement allows a third party system 122,hosting an appropriately configured client application 124, tocommunicate with multiple APIs with a degree of uniformity andpredictability. In one embodiment, a uniform data processing model isutilized and supported by a number of APIs, thereby allowing developersof client applications to reuse parts of their code.

The abstract request and response data processing component 136 of aclient application 124 allows a client application developer to createand modify a client application 124 to communicate with multiple APIsusing a common portion of code. The abstract request and response dataprocessing framework can be reused by a client application 124 for anumber of APIs exposed by the commerce system 12, for example.

Dealing more specifically with the re-usability of the business languageschema data components, in a specific exemplary deployment environmentof a trading environment 10 such as that illustrated in FIG. 1, schemacomponents may be defined such that they can be reused for multiplecases of purchasing and selling items listed via the network-basedcommerce system 12. Examples of such reuse are provided below:

1) Listing an item utilizing an AddItem API: a client application 124may be configured to list an item to be sold in specific regions of theworld, and to recognize acceptable payment and shipment options forpurchasing and shipping items in such a specific region.2) Revising and relisting an item utilizing ReviseItem and RelistItemAPIs: a client application 124 may be configured to enable the revisionand relisting of existing items, such that the item properties arerevised or a completely new listing for the item is created, should theitem not previously have been sold.3) Getting information about an item utilizing GetItem, GetSellerList,or GetBidderList APIs: a client application 124 may be configured toretrieve information about a particular item, or multiple items, thatare actively listed via the network-based commerce system 12.

In all of the above use cases, the client application 124 is required tosend information back to a network-based commerce system 112 regardingitems listed for sale via the commerce system 112. This may requiredescription of an <item> structure in a consistent manner such that theclient applications 122 from which the API calls originate understandthe semantics of an item listed by a seller on the e-commerce system 12.However, since the context of each call from a client application 124 isdifferent in each use case scenario, a different degree of informationneeds to be provided such that some data components are included orexcluded.

Utilizing the item listing use case scenario described above, the issuesdescribed above can be addressed utilizing (1) an <item> data componentmodel, and (2) multiple data validation levels.

Turning first to the <item> data component model, in terms of this modelan “item” has required optional data components. These componentsinternally also have child components that are required and optionalcomponents.

Accordingly, a single item component definition may be used for multipleAPI use cases, with the developers and designers of the APIs being ableto select which elements of the item component must be present and whichelements of an item component do not need to be present.

Turning now to the multiple data validation levels, when a clientapplication 124 sends an API request message payload 172, an APIprocessing payload may, in one embodiment, include the followingsequence of validations:

(a) Schema Level Data Validation: the API request message payload 172 isvalidated with respect to an underlying schema specific to the APImessage payload (e.g., utilizing the XML schema definition for the itemdata component).

(b) API Specific Syntactic Data validation: This involves additionaldata level validation to ensure that the client application 124 has sentrequired data elements that are specified in the XML schema definitionto the option elements, but that are defined as required elements by therelevant API.(c) Business Application Data Validation: This validation involveschecking for a wide range of business application level validations.

The above sequence of validations, it will be noted, utilizes a singledefinition of key business data components such that data variability inrequest/response messages can be supported in a controlled manner usingthe required validation logic for the business use case. For example,for the following the three exemplary APIs (GetItem, GetItem Transactionand SellerList), the same definition of an <item> business definitioncomponent can be used on the client side—yet the APIs will returnresponse messages with varying API data structures. This enablesuniformity in a semantic definition, yet allows the return of differentviews of the <item> business component according to use case. Examplesof response are provided in the attached Computer Program ListingAppendix.

Accordingly, a server system (e.g., a network-based commerce system 12)that exposes multiple business application services can utilize thesemultiple exposed business applications in communicating with multipleclient applications 122 in a way that the client applications 122 canunderstand and communicate. For example, information about an item withvarying syntactic characteristics that correspond to an item iscommunicated (e.g., information about an item with varying syntacticcharacteristics that correspond to a data item component with a commonsemantic definition). The above contributes to the reusability of datacomponents within, for example, a trading community with multiple usecases.

To develop a client application 124 that communicates with multipleAPIs, or to modify an existing client application 124 to talk tomultiple APIs, a developer downloads or imports XML schema definitionsfor each of the multiple APIs. For example, for an exemplaryGetTransactionDetail API, the developer will need to import or downloadthe corresponding schema for this API, and in particular theGetTransactionDetail request message as well as the GetTransactionDetailresponse message. Thereafter, the client application 124 will need tointegrate these schema processing components with their own (e.g., aspart of the API specific component 142).

The above-described business language schema design framework is able tocater for messages being compiled in different data formats, rangingfrom a raw ACP format, to SOAP, to MIME to HTTP. Thus, for example, thesame message data format can be used to transfer a request payload 172from a client application 124 to the server, yet with the responsepayload 196 being sent from the server to the client application 124 ina different message format. From the point of view of the clientapplication 124, a common data processing mechanism may be utilized. Inother words, the request payload 172 and response payload 196 aretransport and message data format independent.

With reference to FIG. 8, in exemplary use case scenarios, the abstractrequest/response message 120 may be extended to an “item listing” usecase 200 and a payment application use case 206. For the item listinguse case 200, an abstract message 120 may be extended to be an Add_ItemRequest/Response message 202 or a Get_Item_Transaction Request/Responsemessage 204. For the payment application use case 206, the abstractmessage 120 may be extended to be a Refund_Transaction Request/Response208 or a Get_Item_Transaction Request/Response 210, merely for example.

An exemplary Get_Item_Transaction Request message is listed below:

<GetItemTransactionsRequest xmlns:xsd=“http://www.w3.org/2001/XMLSchemaxmlns=“urn:marketplace:api:marketplaceAPI”>   <ErrorLanguagexmlns=“urn:marketplace:apis:BLBaseComponents”>en_US</ErrorLanguage>  <Version xmlns=“urn:marketplace:apis:BLBaseComponents”>383</Version>  <EndUserIPxmlns=“urn:marketplace:apis:BLBaseComponents”>10.254.45.68</EndUserIP>  <ItemIDxmlns=“urn:marketplace:apis:BLBaseComponents”>4074744369</ItemID>  <ModTimeFrom>2004-11-10T17:23:00.0664190-08:00</ModTimeFrom>  <ModTimeTo>2004-11-15T17:23:00.0664190-08:00</ModTimeTo> </GetItemTransactionsRequest>  <GetItemTransactionsResponsexmlns:xsd=“http://www.w3.org/2001/XMLSchemaxmlns=“urn:marketplace:api:marketplaceAPI”>   <ns1:Timestampxmlns:ns1=“urn:marketplace:apis:BLBaseComponents”>2004-11-16T01:23:06.453Z</ns1:Timestamp>   <ns2:Ackxmlns:ns2=“urn:marketplace:apis:BLBaseComponents”>Success</ns2:Ack>  <ns3:CorrelationIDxmlns:ns3=“urn:marketplace:apis:BLBaseComponents”>00000000-00000000-00000000-00000000-00000000-00000000-0000000000</ns3:CorrelationID>  <ns4:Versionxmlns:ns4=“urn:marketplace:apis:BLBaseComponents”>383</ns4:Version>  <ns5:Buildxmlns:ns5=“urn:marketplace:apis:BLBaseComponents”>20041112174350</ns5:Build>  <ns6:PaginationResultxmlns:ns6=“urn:marketplace:apis:BLBaseComponents”>   <ns6:TotalNumberOfPages>1</ns6:TotalNumberOfPages>   <ns6:TotalNumberOfEntries>1</ns6:TotalNumberOfEntries>  <ns6:PaginationResult>  <HasMoreTransactions>false</HasMoreTransactions>  <TransactionsPerPage>100</TransactionsPerPage>  <PageNumber>1</PageNumber>  <ReturnedTransactionCountActual>1</ReturnedTransactionCountActual>  <ns7:Item xmlns:ns7=“urn:marketplace:apis:BLBaseComponents”>   <ns7:AutoPay>false</ns7:AutoPay>   <ns7:BuyerProtection>ItemIneligible</ns7:BuyerProtection>   <ns7:Currency>USD</ns7:Currency>   <ns7:ItemID>4074744369</ns7:ItemID>   <ns7:ListingType>Chinese</ns7:ListingType>   <ns7:PaymentMethods>PaymentSeeDescription</ns7:PaymentMethods>   <ns7:PrivateListing>false</ns7:PrivateListing>   <ns7:Quantity>1</ns7:Quantity>    <ns7:Seller>    <ns7:AboutMePage>false</ns7:AboutMePage><ns7:EIASToken>nY+sHZ2PrBmdj6wVnY+sEZ2PrA2dj6wJkoKpC5WCogqdj6x9nY+seQ==</ns7:EIASToken>    <ns7:Email>silkauto_beekde5@ds9.cc</ns7:Email>    <ns7:FeedbackScore>5</ns7:FeedbackScore>    <ns7:FeedbackPrivate>true</ns7:FeedbackPrivate>    <ns7:FeedbackRatingStar>None</ns7:FeedbackRatingStar>    <ns7:IDVerified>true</ns7:IDVerified>    <ns7:NewUser>false</ns7:NewUser>    <ns7:RegistrationDate>1999-01-19T08:00:00.000Z</ns7:RegistrationDate>    <ns7:Site>US</ns7:Site>     <ns7:Status>Confirmed</ns7:Status>    <ns7:UserID>beekde5</ns7:UserID>    <ns7:UserIDChanged>false</ns7:UserIDChanged>    <ns7:UserIDLastChanged>2001-01-19T17:13:05.000Z</ns7:UserIDLastChanged>     <ns7:SellerInfo>     <ns7:AllowPaymentEdit>true</ns7:AllowPaymentEdit>     <ns7:CheckoutEnabled>false</ns7:CheckoutEnabled>     <ns7:CIPBankAccountStored>false</ns7:CIPBankAccountStored>     <ns7:GoodStanding>true</ns7:GoodStanding>     <ns7:LiveAuctionAuthorized>false</ns7:LiveAuctionAuthorized>     <ns7:MerchandizingPref>OptOut</ns7:MerchandizingPref>     <ns7:QualifiesForB2BVAT>false</ns7:QualifiesForB2BVAT>     <ns7:SellerLevel>None</ns7:SellerLevel>     <ns7:StoreOwner>false</ns7:StoreOwner>     </ns7:SellerInfo>   </ns7:Seller>    <ns7:SellingStatus>     <ns7:ConvertedCurrentPricecurrencyID=“USD”>10.0</ns7:ConvertedCurrentPrice>     <ns7:CurrentPricecurrencyID=“USD”>10.0</ns7:CurrentPrice>    <ns7:QuantitySold>1</ns7:QuantitySold>    </ns7:SellingStatus>   <ns7:Site>US</ns7:Site>    <ns7:Title>My ItemTitle</ns7:Title>  </ns7:Item>   <ns8:TransactionArrayxmlns:ns8=“urn:marketplace:apis:BLBaseComponents”>    <ns8:Transaction>    <ns8:AmountPaid currencyID=“USD”>10.0</ns8:AmountPaid>    <ns8:AdjustmentAmount currencyID=“USD”>0.0</ns8:AdjustmentAmount>    <ns8:ConvertedAdjustmentAmountcurrencyID=“USD”>0.0</ns8:ConvertedAdjustmentAmount>     <ns8:Buyer>     <ns8:AboutMePage>false</ns8:AboutMePage><ns8:EIASToken>nY+sHZ2PrBmdj6wVnY+sEZ2PrA2dj6wJkoKjAZKLpA+dj6x9nY+seQ==</ns8:EIASToken>     <ns8:Email>silkauto_ny_buy@unicorn.qa.marketplace.com</ns8:Email>     <ns8:FeedbackScore>0</ns8:FeedbackScore>     <ns8:FeedbackRatingStar>None</ns8:FeedbackRatingStar>     <ns8:IDVerified>false</ns8:IDVerified>     <ns8:NewUser>false</ns8:NewUser>     <ns8:RegistrationDate>2001-12-13T00:56:09.000Z</ns8:RegistrationDate>      <ns8:Site>US</ns8:Site>     <ns8:Status>Confirmed</ns8:Status>     <ns8:UserID>ny_buy</ns8:UserID>     <ns8:UserIDChanged>false</ns8:UserIDChanged>     <ns8:UserIDLastChanged>2002-02-02T00:33:10:000Z</ns8:UserIDLastChanged>      <ns8:BuyerInfo>      <ns8:ShippingAddress>        <ns8:Country>US</ns8:Country>       <ns8:PostalCode>12201</ns8:PostalCode>      </ns8:ShippingAddress>      </ns8:BuyerInfo>     </ns8:Buyer>    <ns8:ShippingDetails>     <ns8:AllowPaymentEdit>false</ns8:AllowPaymentEdit><ns8:ChangePaymentInstructions>false</ns8:ChangePaymentInstructions>     <ns8:InsuranceOption>NotOffered</ns8:InsuranceOption>     <ns8:InsuranceWanted>false</ns8:InsuranceWanted>     <ns8:SalesTax>       <ns8:SalesTaxPercent>0.0</ns8:SalesTaxPercent>      <ns8:ShippingIncludedInTax>false</ns8:ShippingIncludedInTax>     </ns8:SalesTax>     </ns8:ShippingDetails>    <ns8:ConvertedAmountPaidcurrencyID=“USD”>10.0</ns8:ConvertedAmountPaid>    <ns8:ConvertedTransactionPricecurrencyID=“USD”>10.0</ns8:ConvertedTransactionPrice>    <ns8:CreatedDate>2004-11-16T01:22:58.000Z</ns8:CreatedDate>    <ns8:DepositType>None</ns8:DepositType>    <ns8:QuantityPurchased>1</ns8:QuantityPurchased>     <ns8:Status><ns8:marketplacePaymentStatus>NoPaymentFailure</ns8:marketplacePaymentStatus>     <ns8:CheckoutStatus>CheckoutIncomplete</ns8:CheckoutStatus>     <ns8:LastTimeModified>2004-11-16T01:22:58.000Z</ns8:LastTimeModified>     <ns8:PaymentMethodUsed>None</ns8:PaymentMethodUsed>     <ns8:CompleteStatus>Incomplete</ns8:CompleteStatus>    </ns8:Status>     <ns8:TransactionID>0</ns8:TransactionID>    <ns8:TransactionPrice currencyID=“USD”>10.0</ns8:TransactionPrice>   </ns8:Transaction>   </ns8:TransactionArray>  <PayPalPreferred>false</PayPalPreferred> </GetItemTransactionsResponse>

The request/response message exchange between the client application 124and the API server will now be described with reference to FIG. 9. Onthe client application side of the message exchange, the operationsinvolved in the content occasion 124 compiling a request message are asfollows:

receiving data to being included in the request message, indicated byblock 212;

determining the abstract request message payload data 1, comprising, forexample, the required level of detail and the version of the XML schemadefinition for a specific API (e.g. API_0) being used by the clientapplication 124, indicated by block 214;

determining the payload data 2, indicated by block 216;

creating the abstract portion of the message from data 1, indicated byblock 218;

invoking an API-specific component and identifying the API-specific XMLschema definitions, indicated by block 220;

creating the API-specific portion of the message from data 2, using theAPI-specific component, indicated by block 222;

creating an extended request message from the abstract and API-specificportions, indicated by block 224;

enveloping the extended request message in a transport level wrapper,indicated by block 226; and

transmitting the wrapped extended request message via a network to theAPI server, indicated by block 228.

At the API server, the operations involved in compiling a responsemessage for the client application 124 can be summarized as follows:

receiving the client's extended request message, indicated by block 230;

extracting the abstract and extended payload data, indicated by block232;

performing the required version and error check operations, indicated byblock 234;

performing the activity requested in the extended message payload,indicated by block 236;

generating a time stamp, acknowledgement, correlation ID, error andversion data, and including this data into the abstract portion of theresponse messages, indicated by block 238;

identifying the appropriate response data and including this in theextended portion of the response message, indicated by block 240;

creating an extended response message from the abstract and extendedportions, indicated by block 242;

enveloping the extended response message in a transport level wrapper,indicated by block 244; and

transmitting the wrapped extended response message via a network to theclient application, indicated by block 246.

An embodiment of the present invention further utilizes enumerated codetypes. This feature is described with reference to an example, such asthe ListingDuration code type. Enumerated code types can be used forinformation components that may have a fixed set of values. For example,ListingDuration code type identifies how long an item may be listed onthe commerce system 12. There are typically three different values thatListingDuration code type may assume, namely 7, 10 or 14 days. These canbe enumerate in some constant data structure (e.g., weeks) so that, forexample, a duration of 14 days can be formalized with the number “2”.Accordingly, any ListingDuration code type can only correspond to 7, or14 days. If the ListingDuration code type is attributed a value of 21 or15, then such a value would violate the relevant XML schema definition.

According to one embodiment of the present invention, as and provides a“forced element” when encountering a value that violates an XML schemadefinition. Thus, a default value is provided as the enumerated codetype can change over a period of time. Thus, in one month, an originalXML schema definition may define 7, 10, 14 and 21 day duration values,but the next month, the updated up XML schema definition may be updatedto remove the duration value of 21 days. Thus, when a client application124, utilizing the original XML schema, attempt to provide a 21 dayduration value against an updated API, this will be registered as aviolation. To address this, the updated API will insert a “defaultvalue”, which can carry any value, into the response payload 196 of aresponse message 176 provided by the updated API and to the accordingclient application 124.

Thus, an indication of a 21 day duration value duration value againstthe updated API of the commerce system 12 will be accepted, but as theupdated API will issue a warning to the relevant client application 124that it needs to upgrade the relevant XML schema. In use, the defaultvalue is only inserted by the API server into the response message whenthe server detects that the client is using an outdated version of theschema.

FIG. 10 is a flowchart illustrating a method 250, according to anexemplary embodiment of the present invention, of performing versionmanagement between a client application 124 and an API, for exampleimplemented by the commerce system 12. The method 250 illustrates howthe API of the commerce system 12 leverages the business language schemadesign framework described above to communicate back to a clientapplication 124 with client enumerated code types in a scenario in whichthe client application 124 may not be synchronized with a latest versionof an API adopted by the commerce server 12.

The method 250 commences at block 252, with the client application 124including its version identifier (e.g., version ID), identifying theversion of an XML schema definition stored by the client application124, within a request message 158 addressed to a particular target API.An example of the version identifier 170 is provided below:

(Version xmlns=“URN: marketplace: APIs: BLBaseComponents”>383</Version>).

At block 254, an API 126 of the server system 125 receives the requestmessage 158 from the client application 124, and determines from theversion identifier that the client application 124 is utilizing adifferent and older version of an API schema supported by the relevanttarget API 126.

At block 256, the targeted API composes a response message 176,including a response payload 196, and includes within the payloadinstances of specific enumerated code types for an element (e.g., <Site>CustomCode </Site>). This indicates that the API has defined new,additional enumerated codes that may not be understood and correctlyprocessed by the client application 124, in view of its updated XMLschema definition for the targeted API. The “CustomCode” element beingreturned in such scenarios will prevent the client application 124 fromexperiencing a communication breakdown with the API, due to incrementalschema changes and evolutions that may occur as part of the commercesystem 12, for example, revising API-based application serviceofferings.

An enumerate code type examples follow hereunder:

GetUser with Version 383 Returns SiteCode of China Example #1

API client has up-to-date version of API schema to communicate with XMLWeb Service APIs, e.g., GetUser API. Hence, the server system XML WebService API returns the up-to-date enumeration code value (“China”) forthe <Site> enumerated code element.

<?xml version=“1.0” encoding=“utf-16”?> <soap:Envelopexmlns:soap=“http://schemas.xmlsoap.org/soap/envelope/”xmlns:xsi=“http://www.w3.org/2001/XMLSchema-instance”xmlns:xsd=“http://www.w3.org/2001/XMLSchema”>  <soap:Header>  <RequesterCredentials xmlns=“urn:marketplace:api:marketplaceAPI”>   <Credentials xmlns=“urn:marketplace:apis:eBLBaseComponents”>    <AppId>dbeek</AppId>     <DevId>apiteam</DevId>    <AuthCert>apiteamcert</AuthCert>     <Username>soapuser</Username>    <Password>password</Password>    </Credentials>  </RequesterCredentials>  </soap:Header>  <soap:Body>   <GetUserRequestxmlns=“urn:marketplace:api:marketplaceAPI”>    <MessageIDxmlns=“urn:marketplace:apis:eBLBaseComponents”>00cccc08-9875-43a0-97b8-8100a586af4f</MessageID>    <Versionxmlns=“urn:marketplace:apis:eBLBaseComponents”>383</Version>   <EndUserIPxmlns=“urn:marketplace:apis:eBLBaseComponents”>10.254.45.68</EndUserIP>   <UserID>beekde_cn</UserID>   </GetUserRequest>  </soap:Body></soap:Envelope> <?xml version=“1.0” encoding=“utf-16”?><soapenv:Envelopexmlns:soapenv=“http://schemas.xmlsoap.org/soap/envelope/”xmlns:xsd=“http://www.w3.org/2001/XMLSchema”xmlns:xsi=“http://www.w3.org/2001/XMLSchema-instance”>  <soapenv:Body>  <GetUserResponse xmlns=“urn:marketplace:api:marketplaceAPI”>   <ns1:Timestampxmlns:ns1=“urn:marketplace:apis:eBLBaseComponents”>2004-11-24T19:15:52.586Z</ns1:Timestamp>    <ns2:Ackxmlns:ns2=“urn:marketplace:apis:eBLBaseComponents”>Success</ns2:Ack>   <ns3:CorrelationIDxmlns:ns3=“urn:marketplace:apis:eBLBaseComponents”>00cccc08-9875-43a0-97b8-8100a586af4f </ns3:CorrelationID>    <ns4:Versionxmlns:ns4=“urn:marketplace:apis:eBLBaseComponents”>383</ns4:Version>   <ns5:Buildxmlns:ns5=“urn:marketplace:apis:eBLBaseComponents”>20041119132302</ns5:Build>    <ns6:User xmlns:ns6=“urn:marketplace:apis:eBLBaseComponents”>    <ns6:AboutMePage>false</ns6:AboutMePage><ns6:EIASToken>nY+sHZ2PrBmdj6wVnY+sEZ2PrA2dj6wJkoelD5KKpgydj6x9nY+seQ==</ns6:EIASToken>     <ns6:Email>Invalid Request</ns6:Email>    <ns6:FeedbackScore>1</ns6:FeedbackScore>    <ns6:FeedbackRatingStar>None</ns6:FeedbackRatingStar>    <ns6:IDVerified>false</ns6:IDVerified>    <ns6:NewUser>true</ns6:NewUser>    <ns6:RegistrationDate>2004-11-10T23:14:56.000Z</ns6:RegistrationDate>    <ns6:Site>China</ns6:Site>     <ns6:Status>Confirmed</ns6:Status>    <ns6:UserID>beekde_cn</ns6:UserID>    <ns6:UserIDChanged>false</ns6:UserIDChanged>    <ns6:UserIDLastChanged>2004-11-10T23:14:56.000Z</ns6:UserIDLastChanged>     <ns6:BuyerInfo />    <ns6:SellerInfo>     <ns6:AllowPaymentEdit>false</ns6:AllowPaymentEdit>     <ns6:CheckoutEnabled>true</ns6:CheckoutEnabled>     <ns6:CIPBankAccountStored>false</ns6:CIPBankAccountStored>     <ns6:GoodStanding>true</ns6:GoodStanding>     <ns6:LiveAuctionAuthorized>false</ns6:LiveAuctionAuthorized>     <ns6:MerchandizingPref>OptIn</ns6:MerchandizingPref>     <ns6:QualifiesForB2BVAT>false</ns6:QualifiesForB2BVAT>     <ns6:SellerGuaranteeLevel>NotEligible</ns6:SellerGuaranteeLevel>     <ns6:SellerLevel>None</ns6:SellerLevel>      <ns6:SchedulingInfo>      <ns6:MaxScheduledMinutes>30240</ns6:MaxScheduledMinutes>      <ns6:MinScheduledMinutes>0</ns6:MinScheduledMinutes>      <ns6:MaxScheduledItems>1000</ns6:MaxScheduledItems>     </ns6:SchedulingInfo>      <ns6:StoreOwner>false</ns6:StoreOwner>    </ns6:SellerInfo>    </ns6:User>   </GetUserResponse> </soapenv:Body> </soapenv:Envelope>

Example #2

API client has up to-date version of API schema (as specified in<Version> sub-element in GetUserRequest message below) to communicatewith XML Web Service APIs: GetUser API. Hence, XML Web Service APIreturns in response message:

-   -   (a) the default enumeration code value (“CustomCode”) for the        <Site> enumerated code element; and,    -   (b) the <Errors> sub-element also includes information to        indicate to client that client's version of API schema is out of        date:

      <Errors>       <ShortMessage>Warning. Client schema out of date.<ShortMessage>       <LongMessage>Warning. Client schema out of date.Client Schema Version: 361.       Latest Schema Version: 347.LongMessage> GetUser using 361 Version <?xml version=“1.0”encoding=“utf-16”?> <soap:Envelopexmlns:soap=“http://schemas.xmlsoap.org/soap/envelope/”xmlns:xsi=“http://www.w3.org/2001/XMLSchema-instance”xmlns:xsd=“http://www.w3.org/2001/XMLSchema”>  <soap:Header> <RequesterCredentials xmlns=“urn:marketplace:api:marketplaceAPI”>  <Credentials xmlns=“urn:marketplace:apis:eBLBaseComponents”>   <AppId>dbeek</AppId>    <DevId>apiteam</DevId>   <AuthCert>apiteamcert</AuthCert>    <Username>soapuser</Username>   <Password>password</Password>   </Credentials>  </RequesterCredentials>  </soap:Header>  <soap:Body>   <GetUserRequestxmlns=“urn:marketplace:api:marketplaceAPI”>    <MessageIDxmlns=“urn:marketplace:apis:eBLBaseComponents”>b54b5206-901c-43ec-865f-86497e3bab5c</MessageID>    <Versionxmlns=“urn:marketplace:apis:eBLBaseComponents”>361</Version>   <EndUserIPxmlns=“urn:marketplace:apis:eBLBaseComponents”>10.254.45.68</EndUserIP>   <UserID>beekde_cn</UserID>   </GetUserRequest>  </soap:Body></soap:Envelope> <?xml version=“1.0” encoding=“utf-16”?><soapenv:Envelopexmlns:soapenv=“http://schemas.xmlsoap.org/soap/envelope/”xmlns:xsd=“http://www.w3.org/2001/XMLSchema”xmlns:xsi=“http://www.w3.org/2001/XMLSchema-instance”>  <soapenv:Body>  <GetUserResponse xmlns=“urn:marketplace:api:marketplaceAPI”>   <ns1:Timestampxmlns:ns1=“urn:marketplace:apis:eBLBaseComponents”>2004-11-24T19:16:41.445Z</ns1:Timestamp>    <ns2:Ackxmlns:ns2=“urn:marketplace:apis:eBLBaseComponents”>Warning</ns2:Ack>   <ns3:CorrelationIDxmlns:ns3=“urn:marketplace:apis:eBLBaseComponents”>b54b5206-901c-43ec-865f-86497e3bab5c </ns3:CorrelationID>    <ns4:Errorsxmlns:ns4=“urn:marketplace:apis:eBLBaseComponents”>    <ns4:ShortMessage>Warning. Client schema out of date.</ns4:ShortMessage>     <ns4:LongMessage>Warning. Client schema out ofdate. Client Schema Version: 361. marketplace Latest Schema Version:347. </ns4:LongMessage>     <ns4:ErrorCode>14003</ns4:ErrorCode>    <ns4:SeverityCode>Warning</ns4:SeverityCode>    <ns4:ErrorParameters ParamID=“0”>      <ns4:Value>361</ns4:Value>    </ns4:ErrorParameters>     <ns4:ErrorParameters ParamID=“1”>     <ns4:Value>347</ns4:Value>     </ns4:ErrorParameters>   </ns4:Errors>    <ns5:Versionxmlns:ns5=“urn:marketplace:apis:eBLBaseComponents”>383</ns5:Version>   <ns6:Buildxmlns:ns6=“urn:marketplace:apis:eBLBaseComponents”>20041119132302</ns6:Build>    <ns7:User xmlns:ns7=“urn:marketplace:apis:eBLBaseComponents”>    <ns7:AboutMePage>false</ns7:AboutMePage><ns7:EIASToken>nY+sHZ2PrBmdj6wVnY+sEZ2PrA2dj6wJkoelD5KKpgydj6x9nY+seQ==</ns7:EIASToken>     <ns7:Email>Invalid Request</ns7:Email>    <ns7:FeedbackScore>1</ns7:FeedbackScore>    <ns7:FeedbackRatingStar>None</ns7:FeedbackRatingStar>    <ns7:IDVerified>false</ns7:IDVerified>    <ns7:NewUser>true</ns7:NewUser>    <ns7:RegistrationDate>2004-11-10T23:14:56.000Z</ns7:RegistrationDate>    <ns7:Site>CustomCode</ns7:Site>    <ns7:Status>Confirmed</ns7:Status>    <ns7:UserID>beekde_cn</ns7:UserID>    <ns7:UserIDChanged>false</ns7:UserIDChanged>    <ns7:UserIDLastChanged>2004-11-10T23:14:56.000Z</ns7:UserIDLastChanged>     <ns7:BuyerInfo/>    <ns7:SellerInfo>     <ns7:AllowPaymentEdit>false</ns7:AllowPaymentEdit>     <ns7:CheckoutEnabled>true</ns7:CheckoutEnabled>     <ns7:CIPBankAccountStored>false</ns7:CIPBankAccountStored>     <ns7:GoodStanding>true</ns7:GoodStanding>     <ns7:LiveAuctionAuthorized>false</ns7:LiveAuctionAuthorized>     <ns7:MerchandizingPref>OptIn</ns7:MerchandizingPref>     <ns7:QualifiesForB2BVAT>false</ns7:QualifiesForB2BVAT>     <ns7:SellerGuaranteeLevel>NotEligible</ns7:SellerGuaranteeLevel>     <ns7:SellerLevel>None</ns7:SellerLevel>      <ns7:SchedulingInfo>      <ns7:MaxScheduledMinutes>30240</ns7:MaxScheduledMinutes>      <ns7:MinScheduledMinutes>0</ns7:MinScheduledMinutes>      <ns7:MaxScheduledItems>1000</ns7:MaxScheduledItems>     </ns7:SchedulingInfo>      <ns7:StoreOwner>false</ns7:StoreOwner>    </ns7:SellerInfo>    </ns7:User>   </GetUserResponse> </soapenv:Body> </soapenv:Envelope>

FIG. 11 shows a diagrammatic representation of machine in the exemplaryform of a computer system 300 within which a set of instructions, forcausing the machine to perform any one or more of the methodologiesdiscussed herein, may be executed. In alternative embodiments, themachine operates as a standalone device or may be connected (e.g.,networked) to other machines. In a networked deployment, the machine mayoperate in the capacity of a server or a client machine in server-clientnetwork environment, or as a peer machine in a peer-to-peer (ordistributed) network environment. The machine may be a server computer,a client computer, a personal computer (PC), a tablet PC, a set-top box(STB), a Personal Digital Assistant (PDA), a cellular telephone, a webappliance, a network router, switch or bridge, or any machine capable ofexecuting a set of instructions (sequential or otherwise) that specifyactions to be taken by that machine. Further, while only a singlemachine is illustrated, the term “machine” shall also be taken toinclude any collection of machines that individually or jointly executea set (or multiple sets) of instructions to perform any one or more ofthe methodologies discussed herein.

The exemplary computer system 300 includes a processor 302 (e.g., acentral processing unit (CPU) a graphics processing unit (GPU) or both),a main memory 304 and a static memory 306, which communicate with eachother via a bus 308. The computer system 300 may further include a videodisplay unit 310 (e.g., a liquid crystal display (LCD) or a cathode raytube (CRT)). The computer system 300 also includes an alphanumeric inputdevice 312 (e.g., a keyboard), a cursor control device 314 (e.g., amouse), a disk drive unit 316, a signal generation device 318 (e.g., aspeaker) and a network interface device 320.

The disk drive unit 316 includes a machine-readable medium 322 on whichis stored one or more sets of instructions (e.g., software 324)embodying any one or more of the methodologies or functions describedherein. The software 324 may also reside, completely or at leastpartially, within the main memory 304 and/or within the processor 302during execution thereof by the computer system 300, the main memory 304and the processor 302 also constituting machine-readable media.

The software 324 may further be transmitted or received over a network326 via the network interface device 320.

While the machine-readable medium 322 is shown in an exemplaryembodiment to be a single medium, the term “machine-readable medium”should be taken to include a single medium or multiple media (e.g., acentralized or distributed database, and/or associated caches andservers) that store the one or more sets of instructions. The term“machine-readable medium” shall also be taken to include any medium thatis capable of storing, encoding or carrying a set of instructions forexecution by the machine and that cause the machine to perform any oneor more of the methodologies of the present invention. The term“machine-readable medium” shall accordingly be taken to include, but notbe limited to, solid-state memories, optical media and magnetic media.

Although the present invention has been described with reference tospecific exemplary embodiments, it will be evident that variousmodifications and changes may be made to these embodiments withoutdeparting from the broader spirit and scope of the invention.Accordingly, the specification and drawings are to be regarded in anillustrative rather than a restrictive sense.

1. A method of facilitating an exchange of messages between a remoteclient application and a server hosting a plurality of applicationscoupled to at least one Application Programming Interface (API), themethod comprising: receiving in a targeted API a request message fromthe remote client application; the request message having an abstractmessage portion that includes an abstract message payload and anAPI-specific message portion that includes an extended message payloadcomprising a request to perform an activity and a reusable identifiedschema definition specific to the targeted API; performing the activityby calling one or more function calls in the one of the plurality ofapplications from the targeted API; wherein the targeted API facilitatescommunication between the one application and the remote clientapplication.
 2. The method of claim 1 wherein the abstract messageportion is extensible for a plurality of different types of messages. 3.The method of claim 1 wherein the abstract message portion is extensibleover a plurality of different protocols.
 4. The method of claim 1wherein the schema definition is used in a method comprising performingversion and error check operations in the targeted API.
 5. The method ofclaim 4 further including generating a response message that is to besent to the remote client application.
 6. The method of claim 5 whereingenerating a response message includes generating an acknowledgement, atime stamp, a correlation identifier, error data, and version data. 7.The method of claim 1 wherein the server resides in an electronictrading system and the API is responsive to the API-specific messageportion for multiple cases of purchasing and selling items via theelectronic trading system.
 8. The method of claim 7, wherein themultiple cases include at least one case selected from the group ofcases consisting of: listing an item, revising and relisting an item,and getting information about an item.
 9. The method of claim 7 whereinthe API is responsive to the API-specific message portion, such portionhaving an item data component and multiple data validation levels. 10.The method of claim 9 wherein the API-specific message portion furthercomprises an identified schema definition specific to the targeted API,at least one of the multiple data validation levels being selected fromthe group of data validation levels consisting of schema level datavalidation, API specific syntactic data validation, and businessapplication data validation.
 11. A non-transitory computer-readablestorage medium having embedded therein a set of instructions which, whenexecuted by one or more processors of a computer causes the computer toexecute the following operations: using a computer processor, receivingin a targeted API a request message from the remote client application,the request having an abstract message portion that includes an abstractmessage payload and an API-specific message portion that includes anextended message payload comprising a request to perform an activity anda reusable identified schema definition specific to the targeted API,the schema definition used in a method comprising performing version anderror check operations in the targeted API; and performing the activityby calling one or more function calls in the server applications fromthe targeted API, the targeted API facilitating communication betweenthe server application and the remote client application.
 12. Thestorage medium of claim 11 wherein the abstract message portion isextensible for a plurality of different types of messages.
 13. Thestorage medium of claim 11 wherein the abstract message portion isextensible over a plurality of different protocols.
 14. The storagemedium of claim 11 further including generating a response message thatis to be sent to the remote client application.
 15. The storage mediumof claim 14 wherein generating a response message includes generating anacknowledgement, a time stamp, a correlation identifier, error data, andversion data.
 16. The storage medium of claim 11 wherein the serverresides in an electronic trading system and the API is responsive to theAPI-specific message portion for multiple cases of purchasing andselling items via the electronic trading system.
 17. The storage mediumof claim 16, the multiple cases including at least one case selectedfrom the group of cases consisting of listing an item, revising andrelisting an item, and getting information about an item.
 18. Thestorage medium of claim 16 wherein the API is responsive to theAPI-specific message portion, such portion having an item data componentand multiple data validation levels.
 19. The storage medium of claim 18wherein the API-specific message portion further comprises an identifiedschema definition specific to the targeted API, at least one of themultiple data validation levels being selected from the group of datavalidation levels consisting of schema level data validation, APIspecific syntactic data validation, and business application datavalidation.
 20. A system capable of exchanging messages with a remoteclient application, the system comprising: an application server hostinga server application; an Application Programming Interface (API) serverhosting an API capable of providing, to the remote client application,programmatic access to the server application, the API server beingconfigured to: receive a request message from the remote clientapplication, the request message having an abstract message portioncombined with an API-specific message portion, the abstract messageportion having an abstract message payload and the API-specific messageportion having an extended message payload including a request toperform an activity; and perform the activity requested in the extendedmessage payload, the activity performed by calling the serverapplication; wherein the system is in an electronic trading system,wherein the API-specific message portion has an identified schemadefinition specific to the API and the API is responsive to theAPI-specific message portion for multiple cases of purchasing andselling items via the electronic trading system; wherein the applicationserver and the API server each include a processor coupled to a memory;and wherein the API facilitates communication between the serverapplication and the remote client application.
 21. The system of claim20 wherein the abstract message portion is extensible for a plurality ofdifferent types of messages.
 22. The system of claim 20 wherein theabstract message portion is extensible over a plurality of differentprotocols.
 23. The system of claim 20, the multiple cases including atleast one case selected from the group of cases consisting of listing anitem, revising and relisting an item, and getting information about anitem.
 24. The system of claim 23 wherein the API is responsive to theAPI-specific message portion, such portion having an item data componentand multiple data validation levels.
 25. The system of claim 24 whereinthe API-specific message portion further comprises an identified schemadefinition specific to the targeted API, at least one of the multipledata validation levels being selected from the group of data validationlevels consisting of schema level data validation, API specificsyntactic data validation, and business application data validation.